Gray, blue, big, bigger: baleen whales put the mega in “megafauna.” In a new study published on April 4 in the journal Science Advances, researchers discuss the whole-genome sequencing of several of these mammoth species, including the blue whale—the largest animal alive. They found that these marine mammals are related in surprising ways, which could suggest that the most traditional view of evolution isn’t quite right.

Six of the species the researchers studied, including the humpback, fin, sei, minke and blue whale, are part of a family known as rorquals—they’re the baleen whales that have pleated throats, allowing them to gulp huge mouthfuls of seawater that they strain for food using baleen plates. Another baleen whale species, the gray whale, is currently separated into its own taxonomic family. But by sequencing the genomes of these species and applying a new form of scrutiny known as evolutionary network analysis, the researchers were able to demonstrate that the gray whale is also a rorqual, and that it’s closely related to fin and humpback whales: more closely, in fact, than those whales are to other rorquals... [read more]